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European Gypsy Moth Short Range Introduction 2014 Summary
Lymantria dispar dispar
The European Gypsy Moth Short Range Introduction model for 2014 was produced for the Contiguous 48 U.S. (CONUS) at a 240 meter
resolution by the U.S. Forest Service, Forest Health Protection, Forest Health Technology Enterprise Team (FHTET), in collaboration with Animal
and Plant Health Service, Plant Protection and Quarantine (APHIS PPQ) staff, U.S. Geological Survey (USGS), and the European Gypsy Moth
Advisory Group. The intended goal was to develop a spatially explicit model representing the probability of short range gypsy moth introduction from
the known infested area from year to year. Gypsy moth trap data was acquired from the Forest Service, Slow the Spread database (USDA 2013, Tobin
& Blackburn 2007). Introduction was defined as any trap location with a reported trap catch in the current year, but without a trap catch in the year
previous. Persistence was defined as any trap location that reported two consecutive years of positive trap catches for gypsy moth. Traps were not
necessarily placed in the same location from year to year. To account for this, a 200 m radius was used to define overlapping trap locations; a radius of
200 is roughly the distance at which trap locations are thought to be independent based on the effective gypsy moth pheromone trapping distance. The
Software for Assisted Habitat Modeling for VisTrails (SAHM: VisTrails 2013) work flow module was used to investigate various modeling techniques
and predictors datasets for developing the Short Range Introduction surface. A General Linear Model (GLM) was developed between the dependent
variable, gypsy moth introduction locations for 2012; and the independent variable, distance to two year gypsy moth persistence locations (2010 to
2011, Table 1). The model was validated on the introduction locations from 2013 and then applied to create a predictive surface representing the
probability of gypsy moth Short Range Introduction in 2014. The 2014 short range gypsy moth introduction surface was created in ArcGIS 10.1 using
the general linear model equation in raster calculator (Equation 1). The continuous probability values were partitioned into four classes (Table 2), with
the partition between “Moderate” and “Moderate High” corresponding to the threshold at which model sensitivity equals model specificity.
Equation 1: Exp(0.5192 - (0.00004531*"distest.tif"))/(1+Exp(0.5192 - (0.00004531*"distest.tif")))
Table 1: Independent data used in the short range introduction gypsy moth general linear model.
Input
Description and Source
Distant to Nearest
Gypsy Moth Two
Year Persistence
Location
Raster surface representing the distance to nearest gypsy moth two year persistence locations from each year
within the slow the spread trapping area. The “Euclidean Distance” tool in ArcGIS 10.1 was used to create
the distance to nearest gypsy moth establishment layer at 240 m resolution.
SAHM: VisTrails 2013. Talbert, Colin, Talbert Marian, User Documentation for the
Software for Assisted Habitat Modeling (SAHM)
package in VisTrails. U.S. Department of the Interior, U.S. Geological Survey.
http://www.fort.usgs.gov/products/software/sahm/
Tobin, Patrick C.; Blackburn, Laura M., eds. 2007. Slow the Spread: a national program
to manage the gypsy moth. Gen. Tech. Rep. NRS-6. Newtown Square, PA:
U.S.Department of Agriculture, Forest Service, Northern Research Station. 109 p.
Working Group
Downing, Marla C. – USFS FHTET
Leinwand, Ian I. F. – CNT
Withrow, John R. – CNT
Cook, Gericke L. – APHIS PPQ
Kenneway, Lisa F. – APHIS PPQ
Jarnovich, Catherine – USGS
Sapio, Frank J. – USFS FTHET
Table 2: Risk assessment classes
Risk Value
Risk Class
0 to 0.15
Low
> 0.15 to 0.29
Moderate
> 0.29 to 0.45
Moderate High
> 0.45 to 0.63
High
Advisory Group
Chaloux, Paul – APHIS
Lance, David R – APHIS
Liebhold, Andrew – USFS NRS
Man-Son-Hing, Anthony – APHIS
Mastro, Victor C – APHIS
McPherren, Patrick W – APHIS
Spaulding, Julie S – APHIS
USDA, 2013. Forest Service National Gypsy Moth Slow the Spread (STS) program.
http://www.gmsts.org
Point of Contact: Marla C. Downing, USDA Forest Service, Forest Health Protection, Forest Health Technology Enterprise Team (FHTET), 2150 Centre’ Ave., Bldg A, Suite 331
Fort Collins, CO 80526-8121. Phone: 970-295-5843, Email: mdowning@fs.fed.us